Railroad cars are widely used in the United States and other countries to transport vehicles such as automobiles and trucks from manufacturing plants to distribution centers. Such railroad cars are referred to in the trade as auto rack cars.
The railroad cars include a floor and a pair of side walls which, if desired, support at least one, and often two, elevated decks. Additionally, a roof is generally included to protect the vehicles against damage. The floor, and any decks present, carry lined-up vehicles.
It is customary to load, and for railroads to move, a number of such railroad cars in groups hitched together end-to-end and after arrival at a distribution center for the group of railroad cars to be loaded simultaneously. When a group of railroad cars is loaded simultaneously, the vehicles enter at one end and are driven forward as far as possible to a tie down position on one of the railroad cars. This is called circus loading. To make such loading possible the distance between adjoining railroad car ends must be spanned by removable bridge plates at the car floor level and at each deck level. The bridge plates support the vehicle wheels as the vehicles roll from one railroad car to the next.
Vehicles are unloaded from the group of railroad cars in a similar manner, referred to as circus unloading. Vehicles are driven forward from one railroad car to the next over bridge plates and ultimately down ramps, at the forward end of the front car, to the ground.
Stoller et al U.S. Pat. No. 4,437,410 discloses an auto rack railroad car with a closure at each end to prevent vandalism and thievery. Each closure comprises two door assemblies which move horizontally to open and close the car end. The door assemblies are movably supported by a horizontal support member mounted in the interior of the car at the front end or edge of the uppermost of two elevated decks.
Because the door assemblies have a substantial height the bottom of the doors are slidably secured against lateral movement by use of a track or rail, mounted on the railroad car floor, which is engaged by guide means attached at the bottom of the door assemblies. The track or rail has a front run lateral to the car and a run along each side of the car. The entire track guides the door assemblies when the railroad car end is opened and closed by slidable movement of the doors.
Although the guide track for the door assemblies functions satisfactorily as a door guide, it constitutes a ridge which extends upwards about two inches above the floor and reduces the available loading space. Also, when vehicle wheels hit the track, the vehicles bounce. The bouncing can cause the vehicle roof to hit a deck, if present, above it. Also, it can make it difficult for a driver to control the vehicle being unloaded. There is thus a need for an improved guide track which does not interfere with vehicle unloading but which is still able to slidably secure door assemblies in place when in closed position.